Isoforms of TGF-β in the aqueous humor of patients with pseudoexfoliation syndrome and a possible association with the long-term stability of the capsular bag after cataract surgery

Pseudoexfoliation syndrome (PEXS) may go along with capsular bag shrinkage and luxation. In the present study, we focus on an association of isoforms of TGF-beta with capsular bag luxation. Aqueous humor was collected intraoperatively from 20 healthy controls and from 73 otherwise healthy patients with PEXS [PEXS without complications (PEX, n = 33), late PEXS with glaucoma (PEXG, n = 30) and with IOL and capsular bag luxation (PEXL, n = 10)]. The concentrations of TGF-beta 1, TGF-beta 2 and TGF-beta 3 were compared using the Bio-PlexA (R) multiplex beads system based on the non-parametric Kruskal-Wallis H test (p < 0.01). Concentrations of TGF-beta 1, TGF-beta 2 and TGF-beta 3 were higher in the sub-groups PEX and PEXG than in controls (TGF-beta 1; p = 0.009 and 0.0005; TGF-beta 2; p = 0.002 and 0.005 and TGF-beta 3; 0.0005 and 0.0005; respectively), whereas for TGF beta 2, no significant difference between controls and PEXL was revealed (p = 1.0). TGF-beta 2 concentrations were elevated in a similar degree in early PEX and PEXG, but not in PEXL compared to controls (p = 0.002). The concentrations of of TGF-beta 1 and TGF-beta 3 increased in parallel with the progression of disease. The levels of TGF-beta 3, however, did not attain pathophysiological levels (> 100 pg/ml) in any group. A stage-dependent increase in the concentrations of TGF-beta 1 and TGF-beta 3, but not of TGF-beta 2, accords to the shrinkage of the capsular bag. This could increase the tension on the zonular fibers and contribute to luxation of the capsular bag.